对于许多使用规定放疗（RT）治疗的上皮恶性肿瘤而言，治疗延长和中断会对结果产生不良影响。本研究旨在分析接受规定化疗放疗（CRT）治疗的食管癌患者中，放疗持续时间与结果之间的关系。本研究是美国国家癌症研究所赞助的NRG Oncology（原国家外科辅助性乳腺和肠道计划、RTOG和妇科肿瘤研究组）的三项前瞻性、多中心3期随机临床试验（放射治疗肿瘤学组[RTOG] 8501、RTOG 9405和RTOG 0436）次要后续分析。1986年至2013年期间，这些试验中的非转移性食管癌患者接受了规定CRT，随访至2014年。数据分析时间为2022年3月至2023年2月。所有治疗组使用标准剂量RT（50Gy）和同时化疗。研究结果包括局部-区域性复发（LRF）、远处复发、无病生存（DFS）和总生存（OS）。使用多变量模型来研究这些结果与RT持续时间和中断之间的关系。采用X-Tile软件将放疗时间分析为二元变量，选择中位数作为切点和连续变量。本研究包括509名患者（年龄中位数[IQR] 64 [57-70]岁，男性418人[82%]，白种人376人[74%]）。生存患者的中位数[IQR]随访时间为4.01(2.93-4.92)年。RT持续时间的中位数切点在271名患者中为39天或更短（53%），在238名患者中为39天或更长（47%）；而X-Tile软件的切点在446名患者中为45天或更短（88%），在63名患者中为45天或更长（12%）。207名患者（41%）曾经发生过放疗中断。女性（相比男性）和其他族裔（相比白人）与较长的RT持续时间和RT中断有关。在多变量模型中，RT持续时间大于45天与DFS低劣相关（风险比[HR]，1.34；95% CI，1.01-1.77；p = .04）。OS的HR为1.33，但结果未达到统计学意义（95% CI，0.99-1.77；P = .05）。RT持续时间超过39天（相比≤39天）与LRF的风险升高相关（HR，1.32；95% CI，1.06-1.65；P = .01）。作为连续变量，每增加1周的放疗时间与DFS失败有关（HR，1.14；95% CI，1.01-1.28；P = .03）。LRF的HR为1.13，但结果未达到统计学意义（95% CI，0.99-1.28；P = .07）。研究结果表明，接受规定CRT治疗的食管癌患者中，RT持续时间延长与结果低劣相关；女性患者和其他族裔（相比白人）更可能出现较长的RT持续时间和RT中断。最小化放疗中断可优化结果。

For many types of epithelial malignant neoplasms that are treated with definitive radiotherapy (RT), treatment prolongation and interruptions have an adverse effect on outcomes.To analyze the association between RT duration and outcomes in patients with esophageal cancer who were treated with definitive chemoradiotherapy (CRT).This study was an unplanned, post hoc secondary analysis of 3 prospective, multi-institutional phase 3 randomized clinical trials (Radiation Therapy Oncology Group [RTOG] 8501, RTOG 9405, and RTOG 0436) of the National Cancer Institute-sponsored NRG Oncology (formerly the National Surgical Adjuvant Breast and Bowel Project, RTOG, and Gynecologic Oncology Group). Enrolled patients with nonmetastatic esophageal cancer underwent definitive CRT in the trials between 1986 and 2013, with follow-up occurring through 2014. Data analyses were conducted between March 2022 to February 2023.Treatment groups in the trials used standard-dose RT (50 Gy) and concurrent chemotherapy.The outcomes were local-regional failure (LRF), distant failure, disease-free survival (DFS), and overall survival (OS). Multivariable models were used to examine the associations between these outcomes and both RT duration and interruptions. Radiotherapy duration was analyzed as a dichotomized variable using an X-Tile software to choose a cut point and its median value as a cut point, as well as a continuous variable.The analysis included 509 patients (median [IQR] age, 64 [57-70] years; 418 males [82%]; and 376 White individuals [74%]). The median (IQR) follow-up was 4.01 (2.93-4.92) years for surviving patients. The median cut point of RT duration was 39 days or less in 271 patients (53%) vs more than 39 days in 238 patients (47%), and the X-Tile software cut point was 45 days or less in 446 patients (88%) vs more than 45 days in 63 patients (12%). Radiotherapy interruptions occurred in 207 patients (41%). Female (vs male) sex and other (vs White) race and ethnicity were associated with longer RT duration and RT interruptions. In the multivariable models, RT duration longer than 45 days was associated with inferior DFS (hazard ratio [HR], 1.34; 95% CI, 1.01-1.77; P = .04). The HR for OS was 1.33, but the results were not statistically significant (95% CI, 0.99-1.77; P = .05). Radiotherapy duration longer than 39 days (vs ≤39 days) was associated with a higher risk of LRF (HR, 1.32; 95% CI, 1.06-1.65; P = .01). As a continuous variable, RT duration (per 1 week increase) was associated with DFS failure (HR, 1.14; 95% CI, 1.01-1.28; P = .03). The HR for LRF 1.13, but the result was not statistically significant (95% CI, 0.99-1.28; P = .07).Results of this study indicated that in patients with esophageal cancer receiving definitive CRT, prolonged RT duration was associated with inferior outcomes; female patients and those with other (vs White) race and ethnicity were more likely to have longer RT duration and experience RT interruptions. Radiotherapy interruptions should be minimized to optimize outcomes.